PC World has an overview of Loopt, which will begin testing location-based advertising via CBS Mobile in the near future. What’s notable about the service—aside from the fun concept of triangulating location via cell towers—is that Loopt and CBS Mobile “seem to have made most of the right choices for privacy.” That includes the service being opt-in instead of opt-out, and no personal data (such as account info or phone number) being sent back upstream. The targeted ads replace existing ads as well, so there’s not a location-based spammy increase in advertising with the service. This is the kind of advertising we “like”—localized, relevant, and anonymous on our side of things.